This reaction is shown below. In this reaction the ferric ion (Fe 3+) is acting as a Lewis Acid and the oxalate anion (C 2 O 4 2-) as a Lewis Base. A Lewis Acid is an electron pair acceptor and a ...

An acid-base indicator is a substance that changes color as the pH of the solution changes. Indicators work because they are weak acids which when in solution, exist in equilibrium with their ...